China recently tightened its waters controls near the Huangyan Island to prevent Chinese fishing

boats from ________ in the South China Sea.[ ]

A. attacking  

B. having attacked

C. being attacked  

D. having been attacked

制作带模铸造支架填补倒凹的材料，除用超硬石膏外也可用的材料是（）。

A.指甲油

B.强化剂

C.蜂蜡

D.隙料

E.以上都不是